It depends on your beliefs, what your own ideas about what could be called the afterlife are. Some people choose to mourn. I look at it differently. That person had their time, and despite how they used it, good, bad, its over for them. To me there's no use in crying over spilt milk, it's happened and you can't go back in time to change that. If they were close to you, honor their life choices and take what you believe they did right and apply it to your own life.